What is the definition of "hard overtravel limit"?
The physical overtravel limit switch that is the default in the machine. After homing the axes upon start up, the programmed soft travel limit switches become active.

Learn more about hard overtravel limit in the class GE Fanuc Mill: Control Panel Overview 250 below.


CNC Controls: GE Fanuc Training


Class Information
Tooling U-SME classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:GE Fanuc Mill: Control Panel Overview 250
Description:This class describes the various sections of the GE Fanuc 0-C mill control panel as well as the steps for powering up, powering down, and homing the machine. Includes GE Fanuc CNC Simulators.
Prerequisites: 300130  300150  300200  300210 
Difficulty:Intermediate
Number of Lessons:17
Language:English, Spanish
 
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Class Outline
  • Objectives
  • Intro to the GE Fanuc 0-C Mill Control
  • The Operator Panel
  • The Operator Panel Keypad
  • Manual Mode Keys
  • Auto Mode Keys
  • The Control Panel
  • The MDI Keypad
  • The Address and Numeric Keys
  • Special Characters
  • Function Keys and Soft Keys
  • Powering the Machine On and Off
  • Jog Feed
  • Safety Functions
  • Displaying Alarms
  • Homing the Machine
  • Summary
  
Class Objectives
  • Differentiate between the operator panel and the control panel.
  • List the components of the machine panel used for manual adjustments.
  • Identify the different areas of the operator panel.
  • Distinguish between the manual mode keys.
  • Distinguish between the auto mode keys.
  • Identify the main components of the control panel.
  • Distinguish between keys on the MDI keypad.
  • Describe the address and numeric keys.
  • Describe special characters.
  • Distinguish between function keys.
  • List the steps for powering on the machine.
  • Describe a jog feed operation.
  • Describe safety functions.
  • Describe how to display an alarm message.
  • List the steps for homing the machine.

Class Vocabulary

Vocabulary TermDefinition
address key The area of the MDI keypad that allows an operator to enter letters and special characters into the control.
AUTO key The key on the CNC machine that changes the operation mode to auto. Auto mode allows an operator to call up and execute a part program stored in memory. Auto mode is sometimes called memory mode on some CNC controls.
AUTO mode The mode that allows an operator to call up and execute a part program stored in the machine.
auto mode keys The group of keys on the operator panel that control how part programs are used. The AUTO, EDIT, and MDI keys that comprise the program source keys are distinct machine modes.
AUX/GRAPH A function key located on the MDI keypad that displays the graphics screen.
axis selection keys The keys on the machine control panel that allow you to select the X-, Y-, or Z- axis for various operations.
axis/direction keys The area of the machine control that allows an operator to select a specific axis.
BLOCK DELET key A machine control that provides the option of skipping a predetermined series of program blocks. A block delete allows the operator to run two versions of the same program.
brackets [ ]. Punctuation marks used to separate CNC program commands from macro statements.
CAN key A key located on the MDI keypad that backspaces the cursor to delete the last character entered, and cancels any program block that is highlighted during a block edit.
CLNT key A key on a CNC machine control that allows an operator to turn the coolant on and off manually during a program cycle.
control panel The group of controls on a CNC machine that run, store, and edit the commands of a part program and other coordinate information.
cursor keys The up and down arrow keys located on the MDI keypad that enable an operator to move through various screens and fields in the control, edit and search for CNC programs, and move the cursor through the program or screen options.
cycle start key The control button used to begin a program or continue a program that has been previously stopped.
DGNOS/PARAM A function key located on the MDI keypad that displays the diagnostics and parameters screens.
display screen The main screen of the machine that displays important information for the operator.
DNC feed keys The keys on the machine panel that allow the operator to increase feed rate by 1, 10, or 100 times the current feed rate.
DRY RUN key A key that activates the dry run feature on a CNC machine. The dry run function checks a program quickly without cutting parts.
EDIT key The key on the CNC machine that changes the operation mode to edit. Edit mode allows an operator to make changes to a part program and store those changes.
EDIT mode The mode that allows an operator to make changes to a part program and store those changes.
emergency stop Used for emergencies only, the control button that automatically shuts down all machine functions.
end-of-block key EOB. A signal that marks the end of a part program block. An end-of-block signal is represented by a semicolon (;) in a part program.
execution keys The area of the CNC machine control that allows an operator to begin or end a part program. The execution keys include CYCLE START and CYCLE STOP.
feed hold key The control button used to pause a program. Also known as cycle stop, feed hold pauses tool feed but does not stop spindle movement.
feed rate The rate of tool travel through the workpiece per unit of time, generally expressed in inch per revolution (turning) or inch per tooth.
function keys Keys located on the MDI keypad that enable the operator to choose between different tasks.
hard overtravel limit The physical overtravel limit switch that is the default in the machine. After homing the axes upon start up, the programmed soft travel limit switches become active.
HOME key A key that automatically moves the spindle to the machine zero position. The HOME key is sometimes called the zero return key on some machines.
input buffer A temporary location on a computer that holds all incoming information before it continues to the CPU for processing.
input key A key located on the MDI keypad that allows an operator to enter data into the input buffer. This key is also used to input data from an input/output unit.
jog feed In JOG mode, the continuous movement of a tool in a direction along a selected axis.
JOG key The key on the machine control that allows an operator to move a selected axis. Jog keys are often called axis direction keys.
machine function key The area of the control panel that allows an operator to perform different functions depending on what display or mode is selected. The machine function keys include SINGL BLOCK, BLOCK DELET, and DRY RUN.
machine panel The group of controls on a CNC machine that allow an operator to control machine components manually. Sometimes called the operator panel.
machine zero The position located at the farthest possible distance in a positive direction along the machine axes. Machine zero is permanently set for each particular CNC machine.
manual data input keypad The MDI keypad is located on the control panel and houses the address, numeric, and navigation keys.
manual mode keys The keys on the machine panel that allow the operator to jog and home the machine. The manual mode keys include the HOME, JOG, and MPG keys.
manual pulse generator A circular handwheel on a CNC machine that can move a tool incrementally along an axis. On some machines the MPG is known as the "handle."
manual pulse generator keys Keys located on the machine panel that allow the operator to move the tool incrementally along an axis.
MDI key The key on the CNC machine that changes the operation mode to manual data input mode. Manual data input mode lets an operator enter and execute program data without disturbing stored data.
MDI mode An operation mode that lets an operator enter and execute program data without disturbing stored data.
MPG key The key on the operator panel that controls the size of incremental movement of the manual pulse generator.
No. key A key that allows an operator to enter a numerical value into the input buffer. The SHIFT key must be used with the No. key.
numeric keys Keys located on the MDI keypad that allow an operator to enter numbers, a minus sign, and a decimal point into the control. These keys also contain the CAN key, manual JOG arrow keys, the EOB key, the BLOCK DELET, and the right and left cursor move keys.
offset register Area of the machine control that holds tool geometry, wear, and work offset settings.
OFSET A function key located on the MDI keypad that displays tool offsets and settings.
operation keys The keys located on the operator panel that allow an operator to move tools and set offsets.
operator panel The group of controls on a CNC machine that allow an operator to control machine components manually. Sometimes called the machine panel.
OPR/ALARM A function key located on the MDI keypad that displays the alarm screen.
OT Release key The key on the machine panel that allows the operator to move the axis beyond a hard overtravel limit.
outpt/start key A key located on the MDI keypad that allows an operator to start an automatic operation and output data into an input/output unit.
override A machine control component that adjusts programmed values such as speed and feed rate by a certain percentage during operation.
overtravel check A safety function that determines if the tool has moved beyond its set boundaries. Forbidden zones can be programmed to specify areas where the tool can and cannot enter.
page keys The up and down arrow keys located on the MDI keypad that allow an operator to move through various screens and fields one page at a time.
parentheses ( ). Curved brackets used to separate program text information from CNC program commands.
part program A series of instructions used by a CNC machine to perform the necessary sequence of operations to machine a specific workpiece.
POS A function key located on the MDI keypad that displays the position screen that shows axis locations.
power off The red button on a CNC control panel that shuts off power to the control.
power on The green button on a CNC control panel that provides power to the control.
prg stop key The control button used to pause a program. Also known as feed hold, cycle stop pauses tool feed but does not stop spindle movement.
PRGRM A function key located on the MDI keypad that displays the program screen and blocks of the current part program.
program edit keys Keys located on the MDI keypad that allow an operator to alter, insert, or delete data from stored memory.
program protect switch A switch located on the machine control panel that allows the operator to secure current program information. The program protect switch prevents accidental or intentional deletion of programs in memory.
RAPID key The key on the machine control that activates rapid traverse mode.
rapid traverse The movement of machine components at the fastest possible rate of travel. Rapid traverse motion merely requires an endpoint for the movement.
reference position A fixed position on a machine tool to which the tool can easily be moved by the reference position return function.
reset key A key located on the MDI keypad that stops all machine motion and places the program cursor at the top of the current program.
shift key A key located on the MDI keypad that allows an operator to access letters and special characters found on the address keys.
SINGL BLOCK key A key that activates the single block feature on the GE Fanuc 0-C control. The single block function runs the program one block at a time to prove out the program.
soft keys Keys located directly below the display screen that have different purposes depending on which function key has been chosen. The function of each soft key is visible on the display screen between brackets.
SP A key that allows an operator to enter a space when manually entering data.
speed multiply keys Keys that override rates of feed and rapid traverse. The speed multiply keys include the DNC feed keys and the TRVS keys.
spindle keys The area of the CNC machine control that allows the operator to manually control the rotation of the spindle in a clockwise or counter clockwise direction. The spindle keys include CW (clockwise) and CCW (counter clockwise), STOP, and JOG.
TAPE key The key on the machine panel that changes the operational mode of the machine to obtain input from or output to an external tape or hard drive.
TOOL CHANG key The key on the machine panel that allows the operator to select a new tool in the tool magazine.
tool limit switch The component that prevents a tool from exceeding the set direction limit on an axis. The tool limit switch detects overtravel.
tool magazine The component of a CNC mill that holds multiple tools. The tool magazine allows quick changeover from one tool to another.
TRVS keys The keys on the machine panel that allow the operator to increase rapid traverse rate by 25%, 50%, or 100%.
zero return key Also known as the home key, zero return automatically moves the spindle to the machine zero position.